The prior art is replete with filing cabinets for vertically hanging drawings and the like on opposed, horizontally extending pins which are attached to opposite supporting members in the filing cabinet. Many of the filing cabinets disclosed in the prior art utilize curved, or pivoting bar support arrangements. In practice, both of these arrangements are completely impractical and unusable with large quantities of drawings. As a result, large amounts of storage space is either wasted or the drawings are damaged when too many of them are stored in these types of filing systems. Naturally, if a large number of drawings must be safely stored, a large number or incompletely filled filing cabinets must be used with the large attendent increase in cost of the filing system. Many other conventional filing systems use a male and female mating bar assembly which also has tremendous practical difficulties. Drawings kept in male and female mating bar assemblies are difficult to separate and to extract a particular drawing. Additionally, it has been found that in a fully loaded cabinet of this type, the female bar tends to jam within its cooperating male bar and thus causes damage to the cabinet and renders it unusable. Filing cabinet systems of the foregoing type for suspending drawings, documents, sheets and the like are disclosed in the following references: Adams, U.S. Pat. No. 1,335,415 disclosing curved male and female supporting bars; Klitsche, U.S. Pat. No. 1,170,975 disclosing a pair of curved, interconnecting opposed supporting bars; Mobus, U.S. Pat. Nos. 2,205,903 and 2,711,941 disclosing male and female pivoted supporting bars; and Rubissow, U.S. Pat. No. 3,292,982 disclosing telescopic male and female supporting bars which are either straight or curved.
Other types of vertical filing systems disclose horizontal oppositely projecting supporting bars which are attached to relatively movable lathes or vertical dividers. These types of filing systems are disclosed in the Barnhart U.S. Pat. No. 1,416,661 and the Barker Canadian Pat. Nos. 832,899 and 832,900 through 832,902. These systems have at least two major disadvantages. Firstly, it is extremely difficult to view one of the suspended documents without removing it from the filing cabinet and secondly the maximum number of documents storable in this type of filing system is greatly reduced because of the internal dividers and lathes.
The prior art also discloses a plethora of means for hanging the documents from the supporting bars. For example, in the aforementioned Rubissow and Barker patents, the documents themselves are perforated with the resulting holes being reinforced. This system has the obvious disadvantages of permanently disfiguring the documents and relegating the documents for use in only one type of filing cabinet. Other filing systems use expensive and bulky clips which are rigidly attached to the documents. Two such clips are disclosed in the Dannheiser U.S. Pat. No. 923,412 and the aforementioned Adams patent. Still other conventional systems use sheet protectors which totally encompass the drawing or the upper part thereof, such as disclosed in the Amberg Canadian Pat. No. 504,088 or in the aforementioned Mobus patent. All of the foregoing suspension means are bulky, which reduce the number of storable documents, preclude the document from being universally storable, tend to catch on the supporting bars, and/or can damage the document if not carefully used.